Re: machinectl shell policy

From: Dominick Grift <dominick.grift@defensec.nl>
To: Russell Coker <russell@coker.com.au>
Cc: selinux-refpolicy@vger.kernel.org
Subject: Re: machinectl shell policy
Date: Fri, 25 Dec 2020 08:58:41 +0100	[thread overview]
Message-ID: <ypjl8s9m5nbi.fsf@defensec.nl> (raw)
In-Reply-To: <1723812.Y751QtlBzf@liv> (Russell Coker's message of "Fri, 25 Dec 2020 16:12:24 +1100")

Russell Coker <russell@coker.com.au> writes:

> On Thursday, 24 December 2020 7:37:50 PM AEDT Dominick Grift wrote:
>> > To enable "machinectl shell" on recent versions of systemd we need
>> > something like the above policy (which is not complete or ideal, still
>> > doesn't work so no point polishing it) and something for the below.  What
>> > is the below about?
>> this should be thoroughly addressed. machined creates a login pty that
>> gets relabeled on login as per type_change rules.
>
> Currently it's not being relabeled on Debian, but that's a separate issue.

Maybe the required type_change rules arent present?

>
>> > type=USER_AVC msg=audit(1608759091.934:1799): pid=324 uid=108
>> > auid=4294967295 ses=4294967295
>> > subj=system_u:system_r:system_dbusd_t:s0-s0:c0.c1023 msg='avc: denied  {
>> > 0x2 } for msgtype=error
>> > error_name=org.freedesktop.DBus.Error.FileNotFound dest=:1.18 spid=2642
>> > tpid=2706 scontext=system_u:system_r:systemd_machined_t:s0
>> > tcontext=bofh:sysadm_r:sysadm_t:s0-s0:c0.c1023 tclass=(null) permissive=0
>> > exe="/usr/bin/dbus-daemon" sauid=108 hostname=? addr=?
>> > terminal=?'UID="messagebus" AUID="unset" SAUID="messagebus"
>> 
>> Yes i noticed the above as well on debian with dbus-daemon, i dont see
>> any of these on fedora with dbus-broker
>> 
>> By the way we probably shouldnt use the same dbus policy for both
>> dbus-daemon and dbus-broker because theyre pretty different.
>> 
>> * dbus-broker does not check method returns (dbus-daemon does)
>> * dbus-broker is systemd specific (dbus activation works via systemd)
>
> https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=892001
>
> We have work in progress on dbus-broker in Debian.  Would it make sense to 
> only support dbus-broker in SE Linux policy?  Being forced to use only 1 of 
> the 2 dbus programs (and the newer and faster 1 of the 2) is a very small 
> trade-off, smaller than some of the other trade-offs for running SE Linux.

should probably be able to support both (conditionally) but could get messy

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Dominick Grift